Sequencing and functional analysis of the nifENXorf1orf2 gene cluster of Herbaspirillum seropedicae

Klassen, G

doi:10.1016/s0378-1097(99)00533-9

Cited by 12 publications

(27 citation statements)

References 16 publications

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“…The nitrogenase structural genes, other nif genes, and genes involved in the regulation of the nitrogen fixation of H. seropedicae were sequenced. The nif genes were found in two regions; region I contains the genes contiguous with nifA and nifB, while region II contains the nifHDKENXorf1orf2orf3 operon (Machado et al 1996, Klassen et al 1999). The nifQmodABC and fixXC genes are located 3 kbp upstream (Klassen et al 1999).…”

Section: Genetics Studiesmentioning

confidence: 99%

“…The nif genes were found in two regions; region I contains the genes contiguous with nifA and nifB, while region II contains the nifHDKENXorf1orf2orf3 operon (Machado et al 1996, Klassen et al 1999). The nifQmodABC and fixXC genes are located 3 kbp upstream (Klassen et al 1999). The group studied the motif functions present in the promoter region of nifA in detail.…”

Section: Genetics Studiesmentioning

confidence: 99%

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History on the biological nitrogen fixation research in graminaceous plants: special emphasis on the Brazilian experience

Baldani

2005

An. Acad. Bras. Ciênc.

233

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This review covers the history on Biological Nitrogen Fixation (BNF) in Graminaceous plants grown in Brazil, and describes research progress made over the last 40 years, most of which was coordinated by Johanna Döbereiner. One notable accomplishment during this period was the discovery of several nitrogen-fixing bacteria such as the rhizospheric (Beijerinckia fluminensis and Azotobacter paspali), associative (Azospirillum lipoferum, A. brasilense, A. amazonense) and the endophytic (Herbaspirillum seropedicae, H. rubrisubalbicans, Gluconacetobacter diazotrophicus, Burkholderia brasilensis and B. tropica). The role of these diazotrophs in association with grasses, mainly with cereal plants, has been studied and a lot of progress has been achieved in the ecological, physiological, biochemical, and genetic aspects. The mechanisms of colonization and infection of the plant tissues are better understood, and the BNF contribution to the soil/plant system has been determined. Inoculation studies with diazotrophs showed that endophytic bacteria have a much higher BNF contribution potential than associative diazotrophs. In addition, it was found that the plant genotype influences the plant/bacteria association. Recent data suggest that more studies should be conducted on the endophytic association to strengthen the BNF potential. The ongoing genome sequencing programs: RIOGENE (Gluconacetobacter diazotrophicus) and GENOPAR (Herbaspirillum seropedicae) reflect the commitment to the BNF study in Brazil and should allow the country to continue in the forefront of research related to the BNF process in Graminaceous plants.

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Section: Genetics Studiesmentioning

confidence: 99%

Section: Genetics Studiesmentioning

confidence: 99%

History on the biological nitrogen fixation research in graminaceous plants: special emphasis on the Brazilian experience

Baldani

2005

An. Acad. Bras. Ciênc.

233

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“…A similar organization was observed in the phototrophic purple bacterium Rhodobacter capsulatus (Wang et al, 1993). In H. seropedicae, the modA1B1C1 gene cluster probably forms a single operon with the nif genes under the control of the nifH promoter (Machado et al, 1996;Klassen et al, 1999) ( Figure 1A). A modE--like gene, named modE1, is also located in the nif region downstream from the nifA gene and …”

Section: Genetic Organization Of H Seropedicae Modabc Genesmentioning

confidence: 54%

“…Genes coding for a putative ABC-type molybdate transport system (modA1B1C1) were previously found downstream from the nifHDKENXorf1orf2fdxAnifQ genes in H. seropedicae (Klassen et al, 1999). A similar organization was observed in the phototrophic purple bacterium Rhodobacter capsulatus (Wang et al, 1993).…”

Section: Genetic Organization Of H Seropedicae Modabc Genesmentioning

confidence: 70%

Expression, purification and DNA-binding activities of two putative ModE proteins of Herbaspirillum seropedicae (Burkholderiales, Oxalobacteraceae)

et al. 2008

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In prokaryotes molybdenum is taken up by a high-affinity ABC-type transporter system encoded by the modABC genes. The endophyte β-Proteobacterium Herbaspirillum seropedicae has two modABC gene clusters and two genes encoding putative Mo-dependent regulator proteins (ModE1 and ModE2). Analysis of the amino acid sequence of the ModE1 protein of H. seropedicae revealed the presence of an N-terminal domain containing a DNA-binding helix-turn-helix motif (HTH) and a C-terminal domain with a molybdate-binding motif. The second putative regulator protein, ModE2, contains only the helix-turn-helix motif, similar to that observed in some sequenced genomes. We cloned the modE1 (810 bp) and modE2 (372 bp) genes and expressed them in Escherichia coli as His-tagged fusion proteins, which we subsequently purified. The over-expressed recombinant His-ModE1 was insoluble and was purified after solubilization with urea and then on-column refolded during affinity chromatography. The His-ModE2 was expressed as a soluble protein and purified by affinity chromatography. These purified proteins were analyzed by DNA band-shift assays using the modA2 promoter region as probe. Our results indicate that His-ModE1 and His-ModE2 are able to bind to the modA2 promoter region, suggesting that both proteins may play a role in the regulation of molybdenum uptake and metabolism in H. seropedicae.

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“…In some cases, the nifHDK genes are transcribed as a single unit, as observed in several fast-growing rhizobia including Sinorhizobium meliloti (7) and Rhizobium leguminosarum (8) and in the newly described nif cluster from Gluconacetobacter diazotrophicus (9). In other cases, the nifHDK operon contains other nif genes, as reported for Azotobacter vinelandii, where they constitute an operon together with nifTY, orf1 and orf2 (3), Herbaspirillum seropedicae, where they form a large operon composed by nifHDKENXorf1orf2 (10), and Azospirillum brasilense, where they are clustered with orf1 and nifY (4). In other cases, they are separated into two different regions (nifH and nifDK), as shown in the slow-growing species Bradyrhizobium japonicum (11) and Bradyrhizobium sp (Vigna) (cowpea Bradyrhizobia) (12,13).…”

Section: Introductionmentioning

confidence: 74%

Sequencing and promoter analysis of the nifENXorf3orf5fdxAnifQ operon from Azospirillum brasilense Sp7

Potrich

Bressel

Schrank

et al. 2001

Braz J Med Biol Res

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A 40-kb DNA region containing the major cluster of nif genes has been isolated from the Azospirillum brasilense Sp7 genome. In this region three nif operons have been identified: nifHDKorf1Y, nifENXorf3orf5fdxAnifQ and orf2nifUSVorf4. The operons containing nifENX and nifUSV genes are separated from the structural nifHDKorf1Y operon by about 5 kb and 10 kb, respectively. The present study shows the sequence analysis of the 6045-bp DNA region containing the nifENX genes. The deduced amino acid sequences from the open reading frames were compared to the nif gene products of other diazotrophic bacteria and indicate the presence of seven ORFs, all reading in the same direction as that of the nifHDKorf1Y operon. Consensus I 54 and NifA-binding sites are present only in the promoter region upstream of the nifE gene. This promoter is activated by NifA protein and is approximately two-times less active than the nifH promoter, as indicated by the ß-galactosidase assays. This result suggests the differential expression of the nif genes and their respective products in Azospirillum.

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Sequencing and functional analysis of the nifENXorf1orf2 gene cluster of Herbaspirillum seropedicae

Cited by 12 publications

References 16 publications

History on the biological nitrogen fixation research in graminaceous plants: special emphasis on the Brazilian experience

History on the biological nitrogen fixation research in graminaceous plants: special emphasis on the Brazilian experience

Expression, purification and DNA-binding activities of two putative ModE proteins of Herbaspirillum seropedicae (Burkholderiales, Oxalobacteraceae)

Sequencing and promoter analysis of the nifENXorf3orf5fdxAnifQ operon from Azospirillum brasilense Sp7

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